Ixxii INTRODUCTION. 
limestone, Mr D. Sharpe stated :—*that Professor Sedgwick placed the Bala and Coniston 
limestones inthe Upper Cambrian System, which he states to lie below the Silurian System 
of Mr Murchison and above the Lower Cambrian System—a view adopted by Mr Murchison 
in his work on the ‘Silurian System,’ upon the authority of Professor Sedgwick.” 
The assertion implied in the concluding words of this short extract—that Mr Murchi- 
son borrowed from me, or adopted on my authority, his views respecting the relation of 
his Lower Silurian groups to the Upper Cambrian System (the Upper Bala group of the 
Tabular View)—is so directly contrary to fact, that I can only oppose it by a direct denial. 
There is no other way of dealing with it. I do not by any means accuse Mr Sharpe of 
wilfully misrepresenting me. He made a mistake, which, at the time he wrote, might, 
perhaps, be natural; and it only shewed how little acquainted he was with the true 
history of the Silurian System, and with the physical evidence on which it was primarily 
made to rest by its author. 
But what shall I say of the author of the System? He cannot have overlooked this 
passage, because the Paper containing it was the subject of a special comment in his Anni- 
versary Address of 1843. He knew that Mr Sharpe’s statement was historically erroneous— 
so palpably erroneous that a mistake as to that point of error was absolutely impossible. 
Why then did not my friend manfully and instantly rectify this error? The severity of 
historical truth and common candour to myself required this correction. But he never 
made it; and by proceeding to profit by it, he virtually threw the blame of his own mis- 
takes upon myself. Never since the controversy began has he in one instance put himself 
in the right by acknowledging himself in the wrong, even when his mistakes were palpable; 
and in thus masking a part, and by no means an unessential part, of the historical facts, 
he has shewn both a want of candour towards myself, and a want of true wisdom as a 
controversialist. The establishment and extension of his own System was the one object 
he had in view: and the object might be very laudable; and any means of gaining it 
might be right, provided there had been no other labourer in the field. After the lapse of 
twelve years it may be thought unreasonable, on my part, to moot this point of contro- 
versy; but I am now (for reasons given under the next head) compelled to do so, or to 
abandon my own cause altogether; even while I believe it to be the cause, geologically 
and historically, of common sense and common truth. I have not been the aggressor. 
From first to last I have only acted on the defensive : and, so far from showing a prurient 
love of controversy, | have rather shewn, in years past, a lazy and apathetic indifference 
to my own interests as a hard and honest workman at the severe task of an English pale- 
ozoic geologist. 
3. In the new work called “Siluria,’* are the following words: “At that time (1833) 
it was supposed that the slate region of North Wales, then under the examination of 
Professor Sedgwick, consisted of rocks, in part fossiliferous, and of an enormous thickness, 
* John Murray, London, 1854 (pp. 7 and 8). 
